I short circuited the 3V3, 5V0 and the 12V rail in turn. The power supply did shut down, and once the short was removed and the unit switched off for at least one second, resumed normal operation. Although listed here at the beginning of the testing section, I tend to leave this test until the very end, in case it doesn't quite go to plan.

DC Output Voltage Load Regulation:

Mains Input Voltage 110VAC

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 110Vac/50Hz

PSU DC Rail

Measured Voltage(V)

3V3

3.40

5V0

5.08

+12V

12.20

-12V

12.22

5VSB

5.08

Total PSU DC Loading = 0W (0% of Rated Maximum Output Power)

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 110Vac/50Hz

PSU

DC Rail

Rail Loading Amps (A)

Rail Loading Watts (W)

Measured Voltage (V)

ATX12V V2.2 Limits (V)

Pass/Fail

+3V3

3.18

10.78

3.39

3.135 – 3.465

Pass

+5V

4.73

23.93

5.06

4.75 – 5.25

Pass

+12V

15.78

192.20

12.18

11.4 – 12.6

Pass

-12V

0.37

4.51

12.20

10.8 – 13.2

Pass

+5VSB

2.08

10.30

4.95

4.75 – 5.25

Pass

Total PSU DC Loading = 241W (20% of Rated Maximum Output Power)

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 110Vac/50Hz

PSU

DC Rail

Rail Loading Amps (A)

Rail Loading Watts (W)

Measured Voltage (V)

ATX12V V2.2 Limits (V)

Pass/Fail

+3V3

3.18

10.78

3.39

3.135 – 3.465

Pass

+5V

4.71

23.83

5.06

4.75 – 5.25

Pass

+12V

46.22

562.96

12.18

11.4 – 12.6

Pass

-12V

0.37

4.52

12.21

10.8 – 13.2

Pass

+5VSB

2.03

10.05

4.95

4.75 – 5.25

Pass

Total PSU DC Loading = 612W (51% of Rated Maximum Output Power)

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 110Vac/50Hz

PSU

DC Rail

Rail Loading Amps (A)

Rail Loading Watts (W)

Measured Voltage (V)

ATX12V V2.2 Limits (V)

Pass/Fail

+3V3

8.08

27.47

3.40

3.135 – 3.465

Pass

+5V

9.42

47.67

5.06

4.75 – 5.25

Pass

+12V

89.90

1095.88

12.19

11.4 – 12.6

Pass

-12V

0.37

4.52

12.22

10.8 – 13.2

Pass

+5VSB

2.08

10.27

4.94

4.75 – 5.25

Pass

Total PSU DC Loading = 1186W (99% of Rated Maximum Output Power)

Mains Input Voltage 230VAC

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 230Vac/50Hz

PSU DC Rail

Measured Voltage(V)

3V3

3.40

5V0

5.09

+12V

12.20

-12V

12.21

5VSB

5.08

Total PSU DC Loading = 0W (0% of Rated Maximum Output Power)

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 230Vac/50Hz

PSU

DC Rail

Rail Loading Amps (A)

Rail Loading Watts (W)

Measured Voltage (V)

ATX12V V2.2 Limits (V)

Pass/Fail

+3V3

3.19

10.81

3.39

3.135 – 3.465

Pass

+5V

4.75

24.03

5.06

4.75 – 5.25

Pass

+12V

15.72

191.47

12.18

11.4 – 12.6

Pass

-12V

0.37

4.51

12.20

10.8 – 13.2

Pass

+5VSB

2.07

10.16

4.91

4.75 – 5.25

Pass

Total PSU DC Loading = 241W (20% of Rated Maximum Output Power)

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 230Vac/50Hz

PSU

DC Rail

Rail Loading Amps (A)

Rail Loading Watts (W)

Measured Voltage (V)

ATX12V V2.2 Limits (V)

Pass/Fail

+3V3

3.18

10.78

3.39

3.135 – 3.465

Pass

+5V

4.70

23.78

5.06

4.75 – 5.25

Pass

+12V

46.22

562.96

12.18

11.4 – 12.6

Pass

-12V

0.37

4.52

12.21

10.8 – 13.2

Pass

+5VSB

2.03

10.01

4.93

4.75 – 5.25

Pass

Total PSU DC Loading = 612W (51% of Rated Maximum Output Power)

Corsair AX1200 1200W (CMPSU-1200AX) DC Output Voltage Load Regulation

Supply = 230Vac/50Hz

PSU

DC Rail

Rail Loading Amps (A)

Rail Loading Watts (W)

Measured Voltage (V)

ATX12V V2.2 Limits (V)

Pass/Fail

+3V3

8.04

27.34

3.40

3.135 – 3.465

Pass

+5V

9.38

47.46

5.06

4.75 – 5.25

Pass

+12V

89.94

1096.37

12.19

11.4 – 12.6

Pass

-12V

0.38

4.64

12.22

10.8 – 13.2

Pass

+5VSB

2.08

10.27

4.94

4.75 – 5.25

Pass

Total PSU DC Loading = 1186W (99% of Rated Maximum Output Power)

Perfect! Rock solid rails that translate to virtually horizontal lines on the graphs. The Corsair AX1200 power supply is probably one of the best regulated power supplies I've tested, so let's move on and see if it can continue to produce excellent results.